- TOTAL SYNTHESIS OF THE RACEMIC ALKALOID DIPTOCARPAMINE
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A route for the synthesis of racemic diptocarpamine from hex-5-enoic acid has been developed.
- Tolstikova, O. V.,Tolstikov, A. G.,Shmakov, V. S.,Galkin, E. G.,Vyrypaev, E. M.,et al.
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- Modification of the Swern oxidation: Use of stoichiometric amounts of an easily separable, recyclable, and odorless sulfoxide that can be polymer-bound
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Readily available 6-(methylsulfinyl)hexanoic acid (1) is employed as a substitute for DMSO in Swern oxidation reactions using oxalyl chloride to smoothly convert primary or secondary alcohols to corresponding aldehydes or ketones in high yield. The resulting 6-(methylthio)hexanoic acid (2) is easily separable by aqueous extraction or by filtration through silica gel and can be reoxidized to 1 with sodium metaperiodate in 97% yield. Low temperature (-60°C) 13C NMR spectrometry is used to examine the intermediates of this Swern process. The results indicate that any residual unoxidized alcohol is generated during Pummerer elimination of the alkoxysulfonium intermediate and can be minimized by extended exposure to triethylamine at -40°C. Reaction of the potassium salt of 1 with cross-linked chloromethyl polystyrene affords a polymer-bound reagent 12 that quantitatively oxidizes borneol to camphor when used in two-fold excess.
- Liu, Yaoquan,Vederas, John C.
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- Evaluation of methylthio-, methylsulfinyl-, and methylsulfonyl- analogs of alkanes and alkanoic acids as cardiac inotropic and antifungal agents
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A group of alkane and alkanoic acid compounds of general formula MeS(O)(m)(CH2)(n)R [m = 0 - 2; n = 1, 5, 13; R = Me, CO2H(Na)] were synthesized for evaluation as cardiac inotropic and antifungal agents. Inotropic activity was determined as the ability of the test compound to modulate in vitro guinea pig atrium contractility. The oxidation state of the S-atom was an important determinant of inotropic modulation since the thio (m = 0) analogs exhibited a positive inotropic effect. In contrast, the sulfonyl (m = 1) and sulfonyl (m = 2) analogs exhibited a negative inotropic effect. A pentyl spacer (n = 5) provided the largest positive or negative inotropic effect. The relative positive, and negative, inotropic potency orders with respect to the R-substituent were Me ≥ CO2H, and CO2Na ≥ Me, respectively. The most potent positive inotrope MeS(CH2)5Me (EC50 = 4.49 x 10-6 M) could serve as a useful lead-compound for the design of a new class of positive inotropic agents. In a broad spectrum antifungal screen, the minimal inhibitory concentration (MIC) range for the five most active compounds was MeSO2(CH2)5Me (0.46-1.83 mM), MeS(CH2)13Me (0.31-1.23 mM), MeSO(CH2)13Me (2(CH2)13Me (0.27-1.09 mM), and MeS(CH2)13CO2H (0.27-1.09 mM), relative to the reference drug Ampotericin B (2)13Me was selective against C. guillermondi, C. neoformans, S. cerevisiae, and A. fumigatus (strain TIMM 1776).
- Iqbal, Nadeem,McEwen, Carol-Anne,Sardari, Soroush,Daneshtalab, Mohsen,Knaus, Edward E.
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p. 293 - 298
(2007/10/03)
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